20D exposure hold *

[DiaAzul]

I would recommend that you meter the first scene (or pan the camera across the whole scene to determine the most appropriate exposure) then set the camera to manual for the three shots of the panorama. [Initially I thought exposure lock was cancelled between shots, but reading the manual again it is possible to hold the exposure using the * button - I would still recommend setting the camera to manual though to prevent things going squiffy if the exposure doesn't hold. Also, for this type of shot I tend to use a cable release and tripod which makes holding the * button a bit inconvenient]

To keep white balance constant you can take the first image then use the custom white balance function in the menu to set a custom white balance from the first image which can be used for the remaining panorama shots (I am assuming the 20D has the same functionality in this respect as the 1DII). With a bit of practice this shouldn't take too long. Otherwise you can shoot in RAW and set the white balance in the RAW convertor at the time of processing - this is probably a better and more flexible option.

[Q18]

Just a quick question re the exposure hold button (*)

When you press this, it holds the current appeture and shutter value, but, if you are using Auto White Balance, does it also hold the white balance calculated the camera?

I had a scene I wanted to shoot in the morning that I would be making a small panorama out of using 3 seperate shots, I wanted to ensure that the white balance/av/tv were constant but the WB presets have given poor results on my previous try. The last thing I would want though is for the camera to change the WB between shots during the panorama.

Cheers

[Jonathan Wienke]

I second the manual/RAW recommendation. I also strongly recommend using the custom function that maps the * button to autofocus. By NOT pressing * between shots, you can ensure that focust will not be disturbed between shots, either.
Autofocus Tips